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Pekarsky S, Shohami D, Horvitz N, Bowie RCK, Kamath PL, Markin Y, Getz WM, Nathan R. Cranes soar on thermal updrafts behind cold fronts as they migrate across the sea. Proc Biol Sci 2024; 291:20231243. [PMID: 38229520 DOI: 10.1098/rspb.2023.1243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 12/11/2023] [Indexed: 01/18/2024] Open
Abstract
Thermal soaring conditions above the sea have long been assumed absent or too weak for terrestrial migrating birds, forcing obligate soarers to take long detours and avoid sea-crossing, and facultative soarers to cross exclusively by costly flapping flight. Thus, while atmospheric convection does develop at sea and is used by some seabirds, it has been largely ignored in avian migration research. Here, we provide direct evidence for routine thermal soaring over open sea in the common crane, the heaviest facultative soarer known among terrestrial migrating birds. Using high-resolution biologging from 44 cranes tracked across their transcontinental migration over 4 years, we show that soaring performance was no different over sea than over land in mid-latitudes. Sea-soaring occurred predominantly in autumn when large water-air temperature difference followed mid-latitude cyclones. Our findings challenge a fundamental migration research paradigm and suggest that obligate soarers avoid sea-crossing not due to the absence or weakness of thermals but due to their low frequency, for which they cannot compensate with prolonged flapping. Conversely, facultative soarers other than cranes should also be able to use thermals over the sea. Marine cold air outbreaks, imperative to global energy budget and climate, may also be important for bird migration.
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Affiliation(s)
- Sasha Pekarsky
- Movement Ecology Laboratory, Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - David Shohami
- Movement Ecology Laboratory, Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nir Horvitz
- Movement Ecology Laboratory, Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Rauri C K Bowie
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
- Department of Integrative Biology, University of California, Berkeley, CA 94720-3114, USA
| | - Pauline L Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, USA
| | - Yuri Markin
- Oksky State Reserve, pos. Brykin Bor, Spassky raion, Ryazanskaya oblast 391072, Russia
| | - Wayne M Getz
- School Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Ran Nathan
- Movement Ecology Laboratory, Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Turjeman S, Pekarsky S, Corl A, Kamath PL, Getz WM, Bowie RCK, Markin Y, Nathan R. Comparing invasive and noninvasive faecal sampling in wildlife microbiome studies: A case study on wild common cranes. Mol Ecol Resour 2023; 23:359-367. [PMID: 36039836 PMCID: PMC10091961 DOI: 10.1111/1755-0998.13708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 08/05/2022] [Accepted: 08/26/2022] [Indexed: 01/04/2023]
Abstract
In ecological and conservation studies, responsible researchers strive to obtain rich data while minimizing disturbance to wildlife and ecosystems. We assessed if samples collected noninvasively can be used for faecal microbiome research, comparing microbiota of noninvasively collected faecal samples to those collected from trapped common cranes at the same sites over the same periods. We found significant differences in faecal microbial composition (alpha and beta diversity), which likely did not result from noninvasive sample exposure to soil contaminants, as assessed by comparing bacterial oxygen use profiles. Differences might result from trapped birds' exposure to sedatives or stress. We conclude that if all samples are collected in the same manner, comparative analyses are valid, and noninvasive sampling may better represent host faecal microbiota because there are no trapping effects. Experiments with fresh and delayed sample collection can elucidate effects of environmental exposures on microbiota. Further, controlled tests of stressing or sedation may unravel how trapping affects wildlife microbiota.
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Affiliation(s)
- Sondra Turjeman
- Movement Ecology Laboratory, Department of Ecology, Evolution & Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.,Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Sasha Pekarsky
- Movement Ecology Laboratory, Department of Ecology, Evolution & Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ammon Corl
- Museum of Vertebrate Zoology, University of California, Berkeley, California, USA
| | - Pauline L Kamath
- School of Food and Agriculture, University of Maine, Orono, Maine, USA
| | - Wayne M Getz
- Department of Environmental Science, Policy & Management, University of California, Berkeley, California, USA.,School of Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Rauri C K Bowie
- Museum of Vertebrate Zoology, University of California, Berkeley, California, USA.,Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Yuri Markin
- Oksky State Reserve, pos., Brykin Bor, Spassky Raion, Ryazanskaya Oblast, Russia
| | - Ran Nathan
- Movement Ecology Laboratory, Department of Ecology, Evolution & Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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Pekarsky S, Corl A, Turjeman S, Kamath PL, Getz WM, Bowie RCK, Markin Y, Nathan R. Drivers of change and stability in the gut microbiota of an omnivorous avian migrant exposed to artificial food supplementation. Mol Ecol 2021; 30:4723-4739. [PMID: 34260783 DOI: 10.1111/mec.16079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/14/2021] [Accepted: 07/01/2021] [Indexed: 12/21/2022]
Abstract
Human activities shape resources available to wild animals, impacting diet and probably altering their microbiota and overall health. We examined drivers shaping microbiota profiles of common cranes (Grus grus) in agricultural habitats by comparing gut microbiota and crane movement patterns (GPS-tracking) over three periods of their migratory cycle, and by analysing the effect of artificially supplemented food provided as part of a crane-agriculture management programme. We sampled faecal droppings in Russia (nonsupplemented, premigration) and in Israel in late autumn (nonsupplemented, postmigration) and winter (supplemented and nonsupplemented, wintering). As supplemented food is typically homogenous, we predicted lower microbiota diversity and different composition in birds relying on supplementary feeding. We did not observe changes in microbial diversity with food supplementation, as diversity differed only in samples from nonsupplemented wintering sites. However, both food supplementation and season affected bacterial community composition and led to increased abundance of specific genera (mostly Firmicutes). Cranes from the nonsupplemented groups spent most of their time in agricultural fields, probably feeding on residual grain when available, while food-supplemented cranes spent most of their time at the feeding station. Thus, nonsupplemented and food-supplemented diets probably diverge only in winter, when crop rotation and depletion of anthropogenic resources may lead to a more variable diet in nonsupplemented sites. Our results support the role of diet in structuring bacterial communities and show that they undergo both seasonal and human-induced shifts. Movement analyses provide important clues regarding host diet and behaviour towards understanding how human-induced changes shape the gut microbiota in wild animals.
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Affiliation(s)
- Sasha Pekarsky
- Movement Ecology Laboratory, Department of Ecology, Evolution & Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ammon Corl
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California, USA
| | - Sondra Turjeman
- Movement Ecology Laboratory, Department of Ecology, Evolution & Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Pauline L Kamath
- School of Food and Agriculture, University of Maine, Orono, Maine, USA
| | - Wayne M Getz
- Department of Environmental Science, Policy & Management, University of California, Berkeley, California, USA.,School Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Rauri C K Bowie
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, California, USA.,Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Yuri Markin
- Oksky State Reserve, pos. Brykin Bor, Spassky raion, Ryazanskaya oblast, Russia
| | - Ran Nathan
- Movement Ecology Laboratory, Department of Ecology, Evolution & Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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Yu H, Deng J, Nathan R, Kröschel M, Pekarsky S, Li G, Klaassen M. An evaluation of machine learning classifiers for next-generation, continuous-ethogram smart trackers. Mov Ecol 2021; 9:15. [PMID: 33785056 PMCID: PMC8011142 DOI: 10.1186/s40462-021-00245-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/14/2021] [Indexed: 05/16/2023]
Abstract
BACKGROUND Our understanding of movement patterns and behaviours of wildlife has advanced greatly through the use of improved tracking technologies, including application of accelerometry (ACC) across a wide range of taxa. However, most ACC studies either use intermittent sampling that hinders continuity or continuous data logging relying on tracker retrieval for data downloading which is not applicable for long term study. To allow long-term, fine-scale behavioural research, we evaluated a range of machine learning methods for their suitability for continuous on-board classification of ACC data into behaviour categories prior to data transmission. METHODS We tested six supervised machine learning methods, including linear discriminant analysis (LDA), decision tree (DT), support vector machine (SVM), artificial neural network (ANN), random forest (RF) and extreme gradient boosting (XGBoost) to classify behaviour using ACC data from three bird species (white stork Ciconia ciconia, griffon vulture Gyps fulvus and common crane Grus grus) and two mammals (dairy cow Bos taurus and roe deer Capreolus capreolus). RESULTS Using a range of quality criteria, SVM, ANN, RF and XGBoost performed well in determining behaviour from ACC data and their good performance appeared little affected when greatly reducing the number of input features for model training. On-board runtime and storage-requirement tests showed that notably ANN, RF and XGBoost would make suitable on-board classifiers. CONCLUSIONS Our identification of using feature reduction in combination with ANN, RF and XGBoost as suitable methods for on-board behavioural classification of continuous ACC data has considerable potential to benefit movement ecology and behavioural research, wildlife conservation and livestock husbandry.
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Affiliation(s)
- Hui Yu
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
- Druid Technology Co., Ltd, Chengdu, Sichuan, China
| | - Jian Deng
- Druid Technology Co., Ltd, Chengdu, Sichuan, China
| | - Ran Nathan
- The Movement Ecology Laboratory, Department of Evolution, Systematics, and Ecology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Max Kröschel
- Department of Wildlife Ecology, Forest Research Institute of Baden-Württemberg, Freiburg, Germany
- Chair of Wildlife Ecology and Wildlife Management, University of Freiburg, 79106, Freiburg, Germany
| | - Sasha Pekarsky
- The Movement Ecology Laboratory, Department of Evolution, Systematics, and Ecology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Guozheng Li
- Druid Technology Co., Ltd, Chengdu, Sichuan, China.
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China.
| | - Marcel Klaassen
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
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Pekarsky S, Angert A, Haese B, Werner M, Hobson KA, Nathan R. Enriching the isotopic toolbox for migratory connectivity analysis: a new approach for migratory species breeding in remote or unexplored areas. DIVERS DISTRIB 2015. [DOI: 10.1111/ddi.12306] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sasha Pekarsky
- Movement Ecology Lab Dept. of Ecology Evolution & Behavior; Alexander Silberman Institute of Life Sciences; The Hebrew University of Jerusalem; Jerusalem 91904 Israel
| | - Alon Angert
- The Institute of Earth Sciences; The Hebrew University of Jerusalem; Jerusalem 91904 Israel
| | - Barbara Haese
- Alfred Wegener Institute for Polar and Marine Research (AWI); Bussestr. 24 Bremerhaven 27570 Germany
| | - Martin Werner
- Alfred Wegener Institute for Polar and Marine Research (AWI); Bussestr. 24 Bremerhaven 27570 Germany
| | - Keith A. Hobson
- Environment Canada; 11 Innovation Blvd Saskatoon SK Canada S7N 3H5
| | - Ran Nathan
- Movement Ecology Lab Dept. of Ecology Evolution & Behavior; Alexander Silberman Institute of Life Sciences; The Hebrew University of Jerusalem; Jerusalem 91904 Israel
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